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Landscaping and home design for wildfire defense

Home design and retrofitting techniques for wildfire defense

Yana Valachovic Steve Quarles UC Cooperative Extension May 4, 2018

Today’s presentation

How homes burn from wildfire

Near home vegetation and landscaping

Vulnerabilities in home design

Resources

Thank Dr. Steve Quarles, UC fire durability expert (emeritus) now with the Insurance Institute for Business and Home Safety (IBHS), and UC Master Gardener volunteers for many of these slides and ideas.

Homes were the most combustible part of the landscape

Ember / Firebrand

Radiant Heat

Tennessee Division of Forestry

Flame Contact

How a house burns from wildfire?

We Know That …

Wind-blown embers are responsible for the majority of building ignitions

Angora Fire – South Lake Tahoe

USDA FS, R5-TP-015

Embers

Fountain Grove, Santa Rosa 2017

Fuel + Oxygen + Heat = Fire Fuel + Weather + Topography= Fire Behavior What can you control?

Fuel is… anything that will burn

–Dry or dead vegetation –Wood siding, roofing, fencing – Trees –Woody shrubs or perennials – Landscape mulch

Know the basics of fire:

Work from the house out

Defensible Space

Zone 1:

0-5 feet “non-

combustible zone”

Zone 2:

5-30 feet “lean and

green zone”

Zone 3:

30-100 feet or to the

property line “reduced

fuel zone”

0-5 ft “noncombustible zone” to reduce chance of flame contact exposure

Insurance Institute for Business & Home Safety

Insurance Institute for Business & Home Safety

Effective defensible space must be present on all sides of the home

Fire resistant plant lists?

All plants can burn regardless of how they are marketed

Fire safe landscaping requires maintenance (pruning, irrigation, clean-up)

Select low growing, open structured, less resinous, higher moisture content plants

Native and drought tolerant can be options, if maintained well Tubbs Fire, Rich Casale,

NRCS

Mulch helps plants retain moisture, but it will burn too!

Use hardscape, rock mulch or lawns <5 feet from the home.

University of California Cooperative Extension Bark mulch

University of California Cooperative Extension

University of California Cooperative Extension

Pine needle mulch

Tubbs Fire

Simulated embers exposure on a house

Roof (Priority #1)

University of California Cooperative Extension

Roof Edge

©Insurance Institute for Business & Home Safety

Insurance Institute for Business & Home Safety

Insurance Institute for Business & Home Safety

Litter accumulation creates exposure to the wall unit (not protected with roofing).

Insurance Institute for Business & Home Safety

Embers can ignite litter in rain gutters

Plastic gutter vs metal gutter

University of California Cooperative Extension University of California Cooperative Extension

Roof - Skylights

Through-roof (outlet)

Gable end

Foundation & other

Vents (Priority #2)

Under-eave (inlet)

Vents – Ember Entry

Vents – Mesh Size Use 1/8 inch or smaller

6 mm 3 mm

Stephen Quarles

Vents – California’s Chapter 7A

Stephen Quarles

Stephen Quarles

©Insurance Institute for Business & Home Safety

A=foundation vent with intumescent treatment (Vulcan), B=through roof vent with steel wool, C= gable vent with baffles, D= gable vent with intumescent (Embers Out)

A

B

C D

Ridge vents – Vulnerable to debris accumulation

©Insurance Institute for Business & Home Safety

Exterior Walls – Vertical non-combustible zone

©Insurance Institute for Business & Home Safety

©Insurance Institute for Business & Home Safety

©Insurance Institute for Business & Home Safety

University of California Cooperative Extension

University of California Cooperative Extension

Broom

Firewood under a deck

University of California Cooperative Extension

Insurance Institute for Business & Home Safety

Stored building materials under a deck is vulnerable

Fence Vulnerability

Stephen Quarles

Stephen Quarles

A metal gate can help prevent spread to home via a fence ignition.

University of California Cooperative Extension

Fence: Guidance

A neighbor’s house could be in the 5-30 ft zone- their condition can affect your survival

Insurance Institute for Business & Home Safety

Recommendations Good practices: remove stored fuels, debris, clean gutters 1. Roof: install and maintain a Class A rated roof covering.

Install a metal drip edge and address other edge of roof vulnerabilities

2. Vents: upgrade to flame resistant and ember resistant 3. Non-combustible zone should include the area 5’ near the

house, under the entire foot print of the deck, and 6-inches vertically upward from the ground to the start of your siding

Redwood or cedar deck: For ember resistance use a foil faced bitumen tape applied to the top on deck joists, ¼-inch gap between deck boards, and 24-inch on center joist spacing

CA Building Code Chapter 7A WUI construction: http://www.fire.ca.gov/fire_prevention/fire_prevention_wildland_codes

http://osfm.fire.ca.gov/codedevelopment/wildfireprotectionbuildingconstruction

Home design, maintenance, and construction can be more important than any individual fire resistant building product when addressing ember ignition. Poor installation and maintenance can increase the vulnerability of a given product to an ember exposure.

For more information visit: • June 13th webinar- see http://www.cafiresci.org/events-

webinars-source/lessonslearned2017wildfires

• http://ucanr.edu/sites/forestry/Wildfire

From: Home Survival in Wildfire Prone Areas